Textural controls on the brittle deformation of dolomite: variations in peak strength

Textural controls on the peak strength of dolomite are investigated through 23 triaxial deformation experiments, performed at confining pressures of 25, 50, and 100 MPa on texturally diverse dolomites. The mechanical data from these experiments are fit to an empirical failure criterion to elucidate the most significant parameters in dictating the peak strength of dolomite. Neither grain size nor porosity is required to quantitatively predict the peak strength of dolomite. Instead, only the effective Young's modulus, and the empirically predicted uniaxial compressive strength, along with experimentally controlled confining pressure, are required in order to explain the peak strength to and R(2) better than 0.89. A Hall-Petch relationship does not apply to this data set as a consequence of the variability in intragranular and grain boundary textures, which appear to overshadow the role of grain size. It is, therefore, essential that grain boundary textures and intragranular flaws be examined prior to making predictions regarding the relative peak strengths of chemically and mineralogically similar dolomites.